Effective resistance and reactance of a rectangular conductor placed in a semi-closed slot

Swann, S.A.; Salmon, Julia

doi:10.1049/piee.1963.0235

Cited by 29 publications

(8 citation statements)

References 7 publications

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“…Also, considering that the main investigation focuses on the damper windings, it was considered essential to model the amortisseur bars as accurately as possible. In fact, each bar is modelled as a solid conductor to take into account the skin effect due to the higher order slot harmonics [20], [21]. …”

Section: Analysis and Validation Of The Model Of The Sg Test Platmentioning

confidence: 99%

Improved Damper Cage Design for Salient-Pole Synchronous Generators

Nuzzo

Galea

Gerada

et al. 2017

IEEE Trans. Ind. Electron.

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Abstract-The benefits of implementing a damper winding in salient-pole, synchronous generators are widely known and well consolidated. It is also well known that such a winding incurs extra losses in the machine due to a number of reasons. In order to improve the overall efficiency and performance of classical salientpole, wound field, synchronous generators that employ the traditional damper cage, an improved amortisseur winding topology that reduces the inherent loss is proposed and investigated in this paper. This is essential in order to meet modern power quality requirements and to improve the overall performance of such 'classical' machines. The new topology addresses the requirements for lower loss components without compromising the acceptable values of the output voltage total harmonic distortion and achieves this by having a modulated damper bar pitch. As vessel for studying the proposed concept, a 4MVA, salient-pole, synchronous generator is considered. A finite element model of this machine is first built and then validated against experimental results. The validated model is then used to investigate the proposed concept with an optimal solution being achieved via the implementation of a genetic algorithm optimization tool. Finally, the performance of the optimised machine is compared to the original design both at steady state and transient operating conditions.

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Section: Analysis and Validation Of The Model Of The Sg Test Platmentioning

confidence: 99%

Improved Damper Cage Design for Salient-Pole Synchronous Generators

Nuzzo

Galea

Gerada

et al. 2017

IEEE Trans. Ind. Electron.

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“…Fig. 5 shows the equivalent circuit of the damper winding, where k I is the current of the k-th damper loop, which consists of two adjacent damper bars, k E refers to the induced EMF of the k-th bar due to harmonic field, and b Z , e Z refer to the impedance of the damper bar and end-ring connections, which are calculated from dc values and scaled by skin-effect factors [9]. loop and mutual inductance with other loops.…”

Section: Equivalent Damper Circuitmentioning

confidence: 99%

“…The amplitude of harmonic field can be estimated by applying Fourier expansions for the air-gap flux density wave, obtained from (1), and need to be modulated with a flux reduction coefficient which compensates for the decrement in radial harmonic flux from the stator surface to the rotor surface, the flux reduction coefficient g f is derived in (9) according to [11]. …”

Section: Induced Damper Bar Voltagementioning

confidence: 99%

Analytical calculation of damper winding losses in large hydrogenerators

Zhou

et al. 2014

2014 17th International Conference on Electrical Machines and Systems (ICEMS)

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The damper winding is one of the key components of hydro generators. At steady load conditions, currents are induced in the damper winding due to the harmonic field in the air-gap, which lead to parasitic losses in generators. This paper describes an analytical method for calculation of currents and power losses in the damper winding. The described method is based on harmonic analysis of the air-gap magnetic field and the equivalent circuit of the damper winding. The obtained analytical results are compared with values by 2-D transient finite element (FE) studies.

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“…Evolving from solutions of the field equations, expressions have previously been derived 6 for the effective parameters of the rotor bars as functions of slip, and these may be readily interpreted in a form suitable for incorporation into digital-computer programs. In the simplest case of a rectangular bar of depth b in an open slot, for example, the resistance R rh of the bar in terms of the resistance R d at zero frequency takes the form…”

Section: Slip Dependence Of Effective Parameters Of Rotor Barsmentioning

confidence: 99%

Dynamic-response analysis of interconnected synchronous—asynchronous-machine groups. Computer correlation studies with site-test results

Humpage¹,

Durrani²,

Carvalho³

1969

Proc. Inst. Electr. Eng. UK

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Prior to instrumented site tests being carried out on a group of power-station auxiliary motors, computer studies of the site-test conditions were undertaken, and the paper reports the analytical methods developed for the pretest dynamic analyses, together with the correlation achieved between site-test and computed results. For the purposes of the tests, the motors were isolated from the turbogenerator for which they normally function as auxiliaries, and supplied from a neighbouring power station. To assess their recovery to, or divergence from, steady running conditions subsequent to disturbances in the system from which they are supplied, controlled-duration faults were applied at the power station supplying the induction-motor group. In the pretest analyses, 12 subgroups, of a total of 23 motors tested, were independently represented, as was the turbogenerator unit at the neighbouring power station. Central to the analysis is Kron's concept of a synchronously rotating frame of reference, into which the equations of all machines in the group are transformed. It is shown, in the paper, that, after transformation, the machine equations may be arranged in a form particularly suitable for multimachine-system analysis by computer. The overall method of analysis is developed in detail, and its validity is checked by comparisons, made in the paper, of site-test recordings of the principal machine variables, and solutions obtained for them in the pretest computer studies. [Z'] = transient-impedance matrix [C,] [Z] [C]ixi f = angular velocity of synchronously rotating frame of reference . . . d . . p = derivative operator -, time in secondsIn the general formulation of Section 3, suffix b denotes a system-branch quantity and suffix m denotes a machine quantity. In the derivation of the reduced forms of motor and generator representation, suffix s denotes a stator quantity and suffix r denotes a rotor quantity, i.e. for both motor and generator for a generator and l fd kd Jkq. JqrJ for a motorIn. the motor and generator representations, the term total inductance is used for the sum of the magnetising and leakage inductances.

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Effective resistance and reactance of a rectangular conductor placed in a semi-closed slot

Cited by 29 publications

References 7 publications

Improved Damper Cage Design for Salient-Pole Synchronous Generators

Improved Damper Cage Design for Salient-Pole Synchronous Generators

Analytical calculation of damper winding losses in large hydrogenerators

Dynamic-response analysis of interconnected synchronous—asynchronous-machine groups. Computer correlation studies with site-test results

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